Electro-optic switches are used for a variety of applications in which a laser light beam is switched between ON/OFF states. For example, electro-optic switches utilized in telecommunication systems are typically maintained in an OFF state by an applying a bias DC voltage, e.g. −2 volts, to the control input and are switched to a maximum light transmission state (ON) by causing +2 volts to be applied to the control input. This can be accomplished by adding a +4 volt pulse to the −2 volt DC bias. Such electro-optic switches have generally proved successful in such applications.
Problems are associated with a drift of the applied DC bias necessary to keep the switch in a normally OFF state. Charge migration effects within the optical switch cause this drift over time and/or temperature. Failing to maintain the proper DC bias voltage results in the electro-optic switch not being fully OFF, i.e. the maximum attenuation that can be provided by the switch will not be attained. This causes in a decrease in the ON to OFF signal ratio and increases the amount of bleed-through light passing through the switch during the OFF state. Thus, there exists a need for an improvement in controlling electro-optical switches that will minimize this problem.